Emergence pattern,site selection,and seasonal regulation of Onychogomphus costae Selys, 1885 (Odonata: Gomphidae) in northeastern Algeria

Emergence and seasonal regulation of the dragonfly Onychogomphus costae Selys, 1885, were surveyed thoroughly during two consecutive years from two nearby stretches upstream the Seybouse River, northeastern Algeria. The emergence season started in mid-May and lasted 68 and 58 days showing a peak in late May and early June in 2011 and 2012, respectively. During the two years 2011 and 2012, 50% of annual emergence occurred after 25 and 22 days, respectively. Sex ratio was slightly but not significantly male biased. Female exuviae were recorded at higher height than males. Height of the exuviae fixation was positively correlated to support height and head width. Percentage mortality at emergence was mainly due to deformity and predation counting from 7.9% to 9.15% of the total emergent population. The species seasonal regulation is inferred and discussed based on the emergence temporal pattern and larval development.     

The larva of Gomphus davidi Selys, 1887

The female exuvia and last larval stage of Gomphus davidi Selys, 1887, a dragonfly endemic in the Middle East are described and figured. Distinctive characters of two sympatric Gomphus-species are provided.Results of the travels of R. Kinzelbach to the countries of the Middle East, No. 50.     

Emergence depth of triazine susceptible and resistant Solarium nigrum seeds

Effects of population with different origin, biotype, seed size, temperature and depth of burial on the emergence of germinated seeds were investigated to assess the possibilities for successful management of triazine resistant populations of Solanum nigrum. Emergence fraction increased with temperature and decreased with increasing depth of placement. Emergence fraction appeared to be highest at intermediate seed weights. Resistant seeds showed a higher emergence fraction than susceptible seeds while emergence rate of resistant seeds was slightly lower. Emergence rate increased with increasing temperatures and decreasing depths. The possibilities for management of resistant S. nigrum with a stale seedbed preparation are discussed.     

Host-plant susceptibility to the carrot fly, Psila rosae. 2. Suitability of various host species for larval development

Several apiaceous and two asteraceous species were tested for their suitability to support larval development of the carrot fly. Plants grown in pots or transplanted from seed beds into pots, were inoculated with a specific number of eggs. Pupae and non-pupated larvae were collected 6–7 wk after inoculation. Both the number and weights of pupae produced varied widely among the species. Cultivated carrots Daucus carota sativus often gave rise to only moderate numbers of pupae, but these invariably attained the highest weights. Pimpinella major was the only apiaceous plant tested that did not yield any carrot flies. The two asteraceous plants Cichorium intybus and Tanacetum vulgare failed to support larval development. Total carrot fly biomass produced per plant was influenced by both the host species and the root weight. Emergence rates of adult flies were positively correlated with pupal weights. Small individuals tended to have a longer total developmental time from egg to adult fly.     

Effects of Sward Height, Gap Size, and Slug Grazing on Emergence and Establishment of Trollius europaeus (Globeflower)

Abstract To determine the effects of sward height and gap size on the emergence and subsequent development of Trollius europaeus, seeds were introduced into artificially created gaps in mown and unmown wet meadow grassland in Ayr, Scotland. Emergence and establishment of nondormant seed (previously leached in running tap water and soaked in gibberellic acid) placed in a range of circular gaps (25 mm, 50 mm with and without root barrier, 100 and 200 mm diameter) were monitored over 305 days. Trollius demonstrated high field emergence (mean, 46% of viable seed sown) in this experiment. Emergence was not significantly affected by either sward height or gap size, although emergence was greater in mown swards. The critical factor determining subsequent survival of seedlings was slug predation rather than sward height or gap size. However, losses due to slug predation were significantly greater in unmown swards, resulting in more seedlings in mown swards. One hundred eleven days after sowing (September) seedling numbers had declined substantially in both unmown and mown swards, and by day 305 (April) seedlings were extinct in both sward types. The implications of the research for the restoration and management of T. europaeus are discussed.     

TREE SEEDLING EMERGENCE ON INTERACTIVE TEMPERATURE AND MOISTURE GRADIENTS AND IN PATCHES OF OLD-FIELD VEGETATION

Seeds of tree species commonly invading old-fields (Fraxinus americana, Gleditsia triacanthos, Morus rubra, Platanus occidentalis, and Prunus serotina) were germinated at eight temperatures from 5 C to 40 C, with six moisture levels (2% to 18% gravimetric moisture content) at each temperature. For most species, total seedling emergence and emergence rate exhibited approximate bivariate Gaussian response surfaces. Emergence of all species, except Gleditsia, was much more sensitive to differences in temperature than to differences in moisture. Species differed considerably in their response breadths across the interactive gradients, with moisture response bearing little relationship to temperature response. Seeds of Acer saccharum, Crataegus mollis, Fraxinus americana, Gleditsia triacanthos, Morus rubra, and Prunus serotina were sown into old-field vegetation patches dominated by eight different plant species, across three different soils. Acer and Morus emergence exhibited no significant differences among vegetation patches. Emergence of other tree species differed among patch types, but identity of the vegetation (often early successional) most conducive to emergence typically varied from year to year. Emergence of most species responded more strongly to vegetation than to soil series. High Fraxinus and Prunus emergence was associated with dampened temperature ranges, while high Crataegus emergence was associated with low amounts of plant litter. Despite great variability, vegetation differences can predict tree seedling emergence better than do year-to-year or soil differences. Extrapolations from the laboratory experiments predicted approximate levels of overall seedling emergence in the field, but prevailing temperatures and moisture differences among plant neighborhoods alone were not sufficient to explain observed differences in seedling emergence among these patches.     

Life histories,abundance and distribution of some macroinvertebrates from a South Carolina,USA coastal plain stream

The life histories, densities and distribution patterns of the most abundant macroinvertebrates, exclusive of chironomids and oligochaetes, are reported for a low-gradient, second-order, blackwater stream on the Coastal Plain of South Carolina, USA. Univoltine life histories were found for all species of Coleoptera (Ancyronyx variegata, Macronychus glabratus, Dubiraphia quadrinotata and Hydroporus clypealis) and most species of Ephemeroptera (Eurylophella temporalis, Paraleptophlebia volitans and Hexagenia munda), although the mayfly Stenonema modestum was at least bivoltine. Both univoltinism (Macrostemum carolina and Pycnopsyche luculenta), partial bivoltinism (Nyctiophylax affinis) and complete bivoltinism (Hydropsyche decalda, Cheumatopsyche sp., Phylocentropus placidus and probably Chimarra florida) were found among the Trichoptera. Odonate species were both univoltine (Calopteryx dimidiata, Enallagma divagans and Epitheca cynosura) and semivoltine (Boyeria vinosa, Gomphus lividus and Macromia georgina). The alderfly Sialis aequalis and the isopod Asellus laticaudatus were univoltine, while the blackfly Simulium taxodium produced at least 6 generations per year. Groups of functionally-related species within the orders Odonata, Trichoptera and Coleoptera each exhibited possible temporal and/or spatial segregation.     

Spatial distribution, population structure, and fecundity ofCeratozamia matudai lundell (Zamiaceae) in El Triunfo Biosphere Reserve, Chiapas, Mexico

We describe the spatial distribution, population structure, and fecundity ofCeratozamia matudai in two populations in the El Triunfo Biosphere Reserve, in Chiapas, Mexico. Three random plots of 20 × 20 m were laid out in a cypress forest habitat of the cycad and six plots in a cloud forest habitat on Mount Ovando. The aggregated spatial pattern ofC. matudai showed a clumped local distribution on shallow soils on steep slopes. Individuals between the sites showed differences in leaf production, trunk diameter, height, and growth pattern. A population structure with an inverse “J” curve was obtained in both sites. Emergence of male and female cones appears to be synchronous in both populations, with a predominance of male cones recorded.     

Temporal dynamics and relationship between climate,limnological variables and zooplankton composition in climate-sensitive Lake Bosumtwi,Ghana

The community composition and the factors affecting seasonal and interannual dynamics of zooplankton in Lake Bosumtwi were studied biweekly at a central index station during 2005 and 2006. The lake zooplankton community was species poor. Mesocyclops bosumtwii was numerically superior seasonally and interannually and was endemic to the lake. Minor constituents included Moina micrura, six rotifer species (except for Hexarthra intermedia) and Chaoborus ceratopogones larvae. Low variance of cyanobacteria-dominated phytoplankton biomass underlined stable zooplankton community structure. Emergence of rare species of rotifers occurred seasonally. The climatic signature on the lake’s stratification and mixing regime was strongly influenced by atmospheric temperature, but weakly by wind strength, because of sheltering of the lake by high crater walls. Increasing mixing depth entrained high TP concentrations from below the thermocline seasonally, but reflected poorly in the phytoplankton biomass behaviour. Total zooplankton abundance did not differ seasonally, but varied markedly from year to year in its timing and magnitude. Herbivores were squeezed between food limitation and high predation pressure from Chaoborus all year round. The low fish planktivory (high fishing pressure) on Chaoborus may create a trophic bottleneck restricting energy transfer efficiency from zooplankton to fish.     

Long-term storage of sexual and asexual Trichogramma brassicae (Hymenoptera: Trichogrammatidae)

The effect of exposure duration to pre-storage (representing fall conditions) and storage (representing winter conditions) temperatures on the emergence rate in sexual and asexual Trichogramma brassicae Bezdenko (Hymenoptera: Trichogrammatidae) was studied under controlled laboratory conditions. Asexual T. brassicae was infected by Wolbachia, an endosymbiont bacterium. We considered 0, 30, 40, 50 and 60 days as exposure duration at 10°C and 0, 30, 60, 90 followed by 180 days as exposure duration at 4°C for both T. brassicae strains. Emergence rate was significantly affected by the presence of Wolbachia, the duration of exposure to 10°C, the duration of storage at 4°C and their interactions, but not by the interaction between strain × storage duration at 4°C. Emergence rate of adults was positively correlated with exposure duration at 10°C, but it gradually decreased as the cold storage duration (4°C) increased in both strains. In conclusion, we are able to store both asexual and sexual strains for longer periods of time at 4°C, but the emergence rate of sexual T. brassicae was greater than asexual in all the treatments. The presence of Wolbachia could have a negative effect on fitness of T. brassicae and reduces its emergence rate after long-term storage.     

Effects of population density, sex morph, and tree size on reproduction in a heterodichogamous maple, Acer mono, in a temperate forest of Japan

The effects of local population density, sex morph [protogynous (PG) or protandrous (PA)], and individual tree size on the demographic processes of seed production were investigated in a heterodichogamous maple, Acer mono Maxim. var. Marmoratum (Nichols.) Hara f. dissectum, in a temperate forest of Japan. As the distance from conspecific reproductive adults increased, the percentage of immature seed fall and empty seeds increased significantly, indicating higher pollination success along with local population density. Although the difference was not distinct, pollination success was affected by the local population density of the reciprocal sex morph rather than that of both sex morphs. The trees at higher local population density sites suffered higher seed mortality due to predation and decay, and tended to produce smaller seeds. Thus, the impacts of local population density operated both positively and negatively on reproduction. As a factor of individual traits, tree size scarcely affected any demographic processes. On the other hand, sex morph did affect pollination success. Trees of PG type had lower immature seed fall than those of PA type, suggesting that the former has higher efficiency of pollen acceptance than the latter. The results on seed demography presented here partly support previous suggestions that heterodichogamous plants exhibit reciprocal cross-pollination and gender specialization as reproductive traits.     

Seed survival and seasonal emergence in some species of Geranium, Ranunculus and Rumex

Seeds of 14 species were collected, usually in each of 2 or 3 yr, and mixed with the top 7.5 cm of sterilised soil confined in cylinders sunk in the ground outdoors and cultivated three times yearly. Seedling emergence was recorded for at least 3 and usually 5 yr. Most seedlings of Ranunculus bulbosus and Rumex acetosa appeared during the autumn of sowing, while the main emergence of Geranium pratense. Ranunculus acris, Rumex conglomeratus and R. maritimus was in the following spring. Emergence of G. pyrenaicum and G. robertianum took place throughout much of the year after sowing. Seeds of all these species were relatively short-lived in cultivated soil, and few seedlings appeared after the second year. Seed survival was greater in G. dissectum. G. molle, Rumex acetosella. Ranunculus sceleratus and especially R. repens, of which emergence in the fifth year after sowing amounted to 4% of the seeds sown. Emergence from the persistent seed bank was mainly from May to September for G. dissectum and G. molle and during autumn for Ranunculus flammula and R. sceleratus, while seedlings of Ranunculus repens and Rumex acetosella appeared sporadically over most of the year.     

Comparison of the life cycles of two mayfly species between upper and lower parts of the same stream

The life cycles of the burrowing mayflies, Ephemera strigata Eaton and E. japonica McLach‐lan were studied comparatively between upper part and lower part of a small tributary of the Yoshino River. E. strigata was more common than E. japonica in the studies areas. E. japonica was found only in the upper part and in tiny tributaries of the stream. E. strigata was univoltine in the lower and in the upper parts of the stream. However, the population falls into two groups, one of which emerges in early May and the other in summer. Water temperature seems to be one of the factors affecting the variable life cycle of E. strigata. E. japonica is univoltine. Emergence of this species was observed from June to August.     

Spatial Distribution,Food and Activity of Gomphus pulchellus SELYS 1840 (Insecta; Odonata; Gomphidae) from a Still Water Habitat

Distribution patterns of Gomphus pulchellus larvae in different sediments with different density of prey organisms were studied in the field in a small gravel pit lake in the south of Germany. Larval burrowing behaviour at different temperatures as well as food preference, consumption rates and activity were studied in laboratory experiments. In the study lake G. pulchellus larvae lived exclusively in places where macrophytes were present and in fine sediments (mean grain size <3 mm) with detritus cover. There was a significant positive correlation between larval density and density of food organisms suggesting that abundance of food is one of the determinants of larval distribution. In late autumn larvae migrated to deeper places probably to survive the winter. Low temperatures simulated in laboratory experiments did not induce larvae to burrow deeper. Larvae were always found in a sediment depth of 0.59–0.74 cm. Experiments with mixed prey showed that G. pulchellus larvae preferred tubificid worms and chironomid larvae over gammarids and ephemerid larvae. However, chironomid larvae which stayed in their tubes had a higher survival rate than those outside of tubes. Single-prey experiments showed that G. pulchellus larvae can prey not only on benthic species but also on Daphnia from the open water. Functional-response experiments showed that one G. pulchellus larva consumes a maximum of 2 to 3 tubificid worms or chironomid larvae per day, which corresponds to a maximum biomass (freshweight) of 5 to 30 mg per day. Video recordings of activity showed that G. pulchellus larvae cover long distances of up to 52 m per night on the substrate surface and that activity on the substrate surface started after midnight and ceased before sunrise. Consumption of Zooplankton prey and high activity above the substrate is interpreted as an adaptation of G. pulchellus larvae to the life in still water habitats.     

Synchronization of reproductive period among the two male forms and female of the damselflyMnais pruinosa selys (Zygoptera: Calopterygidae)

Ecological parameters in a population ofMnais pruinosa were investigated in a mountain stream. In the study area, there were two forms of male with regard to wing color, the orange-winged male (esakii) and the hyaline-winged male (strigata), and only one female form with hyaline wings. Emergence of adults began in late April, and the flying season ended in late June. The time after emergence was spent in maturation, and the insects began to mate when they reached maturity. Longevity of adults was 17.6 days foresakii males, 18.4 days forstrigata males and 21.9 days for females. There was little difference in emergence time, maturation period, survivorship curve and longevity among the two male forms and female. In other words, the period for reproductive activities was perfectly coincident among them. The factors influencing the synchronization of emergence were discussed.     

Genetic diversity in the blackberry rust pathogen, Phragmidium violaceum, in Europe and Australasia as revealed by analysis of SAMPL

Indigenous to Europe, the blackberry rust fungus Phragmidium violaceum was introduced to Australia and subsequently appeared in New Zealand, with the most recent authorised introductions to Australia specifically for the biological control of European blackberry. Markers for ‘selective amplification of microsatellite polymorphic loci’ (SAMPL) were developed for studying the population genetics of P. violaceum. Modification of one of the two SAMPL primers with a HaeIII adapter (H) revealed significantly greater levels of genetic variation than primers used to generate AFLPs, the latter revealing little or no variation among 25 Australasian and 19 European isolates of P. violaceum. SAMPL was used to describe genetic variation among these 44 isolates of P. violaceum from 51 loci generated using primer pairs (GACA)₄ + H–G and R1 + H–G. The European isolates were more diverse than Australasian isolates, with 37 and 22 % polymorphic loci, respectively. Cluster analysis revealed geographic clades, with Australasian isolates forming one cluster separated from two clusters comprising the European isolates. However, low bootstrap support at these clades suggested that Australian isolates had not differentiated significantly from European isolates since the first record of P. violaceum in Australia in 1984. In general, the results support two hypotheses. First, that the population of P. violaceum in Australia was founded from a subset of individuals originating from Europe. Second, that P. violaceum in New Zealand originated from the Australian population of P. violaceum, probably by wind dispersal of urediniospores across the Tasman Sea. The application of SAMPL markers to the current biological control programme for European blackberry is discussed.     

Cryptic Sex in Symbiodinium (Alveolata,Dinoflagellata) is Supported by an Inventory of Meiotic Genes

Symbiodinium encompasses a diverse clade of dinoflagellates that are ecologically important as symbionts of corals and other marine organisms. Despite decades of study, cytological evidence of sex (karyogamy and meiosis) has not been demonstrated in Symbiodinium, although molecular population genetic patterns support the occurrence of sexual recombination. Here, we provide additional support for sex in Symbiodinium by uncovering six meiosis‐specific and 25 meiosis‐related genes in three published genomes. Cryptic sex may be occurring in Symbiodinium's seldom‐seen free‐living state while being inactive in the symbiotic state.     

Proportion of mated females, female mating experience, and sex ratio of the osmund sawfly, Strongylogaster osmundae (Hymenoptera, Tenthredinidae)

The proportion of mated females (M _f) of the osmund sawfly, Strongylogaster osmundae, and the sex ratio of the eggs they deposited (r, proportion of males) were estimated in the wild by collecting egg masses. The proportion of mated females at oviposition varied from 0 to 1.0. M _f was high (often 1.0) among the females that emerged after hibernation, and lower in the subsequent generations. Mated females of the hibernated generation deposited equal numbers of eggs of both sexes. Mated females of the first and subsequent generations produced more female than male eggs. These results qualitatively agreed with the prediction provided by an evolutionarily stable strategy (ESS) model (if M _f < 1 then r < 0.5). However, the quantitative prediction provided by the model [M _f (1 − r) = 0.5] was not always observed in the wild, especially where the population density and M _f were high. The value of r was often lower than the predicted one. The following simple hypothesis was tested by experimentation: “Females that encounter males frequently estimate the proportion of mated females to be high and deposit eggs with a 1:1 sex ratio.” However, results did not support this hypothesis. Females that copulated soon after emergence and were courted by males two or more times did not show a higher offspring sex ratio than those which mated 1 or 2 days after emergence and experienced no other sexual encounter. Another mechanism for determination of r is suggested, and the reason why the population sex ratio of sawflies is often female-biased (r < 0.5) is discussed.     

Analysis of the emergence of the Scarce Chaser Libellula fulva O.F. Müller, 1764 (Odonata: Libellulidae)

The Scarce Chaser (Libellula fulva) is widespread in Europe and in many regions is relatively common. It is also abundant in the lake districts of western and northern Poland. Although the species frequently occurs in large numbers its biology is poorly known. Emergence of L. fulva was investigated in this study as a contribution to the life history of the species. Studies were carried out in the vicinity of Chojno (52°41′ N, 16°12′ E) on the edge of the Notecka Forest in 2003 and 2004. The stem habitat of the population is a stream with the adjacent swamps. Libellula fulva belongs to the spring species sensu Corbet (1999). The emergence of the studied population lasted 19 days (between 18 May and 5 June) and 31 days (between 13 May and 12 June) in 2003 and 2004, respectively. It was characterised by synchronous and, especially in the first phase, mass emergence. The high synchronisation is reflected in the fact that 50% of the population had emerged by the seventh (in 2003) and the fifth (in 2004) days of the process. This is vital to the imagines, which mature and return to the water body as soon as possible to reproduce. Timing of the end of emergence depends on atmospheric conditions during its duration and the conditions preceding the start of emergence on a given day. In the daily course there is a tendency for emergence to finish as soon as possible. Extension of the emergence is synonymous with increased mortality in the dragonfly population caused by predators.     

Emergence, basking behaviour, mean selected temperature and critical thermal minimum in high and low altitude subspecies of the tropical lizard Mabuya striata

Emergence, basking behaviour, selected temperature, and critical thermal minimum were studied in warm and cold acclimated groups of two subspecies of the lizard Mabuya striata. The high-altitude M. s. punctatissima emerges earlier than the low-altitude M. s. striata. Under conditions of warm acclimation, M. s. punctatissima has a longer initial bask. The two subspecies do not differ in either mean selected temperature or critical thermal minimum, although in both cases values for cold acclimated lizards are lower than for warm acclimated lizards. I have previously demonstrated differences between the subspecies in the pattern of thermal acclimation of rate of oxygen consumption. I thus consider that M. striata is static in some aspects of its thermal biology but labile in others.